Many medications are delivered to a patient from an intravenous (IV) bag into which a quantity of a medication is introduced. Sometimes, the medication may be an admixture with a diluent. In some cases, the IV bag contains only the medication and diluent. In other cases, the IV bag may also contain a carrier or other material to be infused into the patient simultaneously with the medication. Medication can also be delivered to a patient using a syringe.
Medication is often supplied in dry (e.g., powder) form in a medication container such as a vial. A diluent liquid in a separate or diluent container or vial may be supplied for reconstituting with the medication. The resulting medication may then be delivered to a patient according to the prescription.
One function of the pharmacist is to prepare a dispensing container, such as an IV bag or a syringe, which contains a proper amount of diluent and medication according to the prescription for that patient. Some prescriptions (e.g., insulin) may be prepared to suit a large number of certain types of patients (e.g., diabetics). In such cases, a number of similar IV bags containing similar medication can be prepared in a batch, although volumes of each dose may vary, for example. Other prescriptions, such as those involving chemotherapy drugs, may call for very accurate and careful control of diluent and medication to satisfy a prescription that is tailored to the needs of an individual patient.
The preparation of a prescription in a syringe or an IV bag may involve, for example, transferring fluids, such as medication or diluent, among vials, syringes, and/or IV bags. IV bags are typically flexible, and may readily change shape as the volume of fluid they contain changes. IV bags, vials, and syringes are commercially available in a range of sizes, shapes, and designs.